/*!
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* XRegExp.build 4.0.0
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* <xregexp.com>
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* Steven Levithan (c) 2012-2017 MIT License
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*/
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export default (XRegExp) => {
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const REGEX_DATA = 'xregexp';
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const subParts = /(\()(?!\?)|\\([1-9]\d*)|\\[\s\S]|\[(?:[^\\\]]|\\[\s\S])*\]/g;
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const parts = XRegExp.union([/\({{([\w$]+)}}\)|{{([\w$]+)}}/, subParts], 'g', {
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conjunction: 'or'
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});
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/**
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* Strips a leading `^` and trailing unescaped `$`, if both are present.
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*
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* @private
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* @param {String} pattern Pattern to process.
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* @returns {String} Pattern with edge anchors removed.
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*/
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function deanchor(pattern) {
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// Allow any number of empty noncapturing groups before/after anchors, because regexes
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// built/generated by XRegExp sometimes include them
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const leadingAnchor = /^(?:\(\?:\))*\^/;
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const trailingAnchor = /\$(?:\(\?:\))*$/;
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if (
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leadingAnchor.test(pattern) &&
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trailingAnchor.test(pattern) &&
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// Ensure that the trailing `$` isn't escaped
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trailingAnchor.test(pattern.replace(/\\[\s\S]/g, ''))
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) {
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return pattern.replace(leadingAnchor, '').replace(trailingAnchor, '');
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}
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return pattern;
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}
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/**
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* Converts the provided value to an XRegExp. Native RegExp flags are not preserved.
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*
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* @private
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* @param {String|RegExp} value Value to convert.
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* @param {Boolean} [addFlagX] Whether to apply the `x` flag in cases when `value` is not
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* already a regex generated by XRegExp
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* @returns {RegExp} XRegExp object with XRegExp syntax applied.
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*/
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function asXRegExp(value, addFlagX) {
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const flags = addFlagX ? 'x' : '';
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return XRegExp.isRegExp(value) ?
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(value[REGEX_DATA] && value[REGEX_DATA].captureNames ?
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// Don't recompile, to preserve capture names
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value :
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// Recompile as XRegExp
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XRegExp(value.source, flags)
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) :
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// Compile string as XRegExp
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XRegExp(value, flags);
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}
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function interpolate(substitution) {
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return substitution instanceof RegExp ? substitution : XRegExp.escape(substitution);
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}
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function reduceToSubpatternsObject(subpatterns, interpolated, subpatternIndex) {
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subpatterns[`subpattern${subpatternIndex}`] = interpolated;
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return subpatterns;
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}
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function embedSubpatternAfter(raw, subpatternIndex, rawLiterals) {
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const hasSubpattern = subpatternIndex < rawLiterals.length - 1;
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return raw + (hasSubpattern ? `{{subpattern${subpatternIndex}}}` : '');
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}
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/**
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* Provides tagged template literals that create regexes with XRegExp syntax and flags. The
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* provided pattern is handled as a raw string, so backslashes don't need to be escaped.
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*
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* Interpolation of strings and regexes shares the features of `XRegExp.build`. Interpolated
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* patterns are treated as atomic units when quantified, interpolated strings have their special
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* characters escaped, a leading `^` and trailing unescaped `$` are stripped from interpolated
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* regexes if both are present, and any backreferences within an interpolated regex are
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* rewritten to work within the overall pattern.
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*
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* @memberOf XRegExp
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* @param {String} [flags] Any combination of XRegExp flags.
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* @returns {Function} Handler for template literals that construct regexes with XRegExp syntax.
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* @example
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*
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* const h12 = /1[0-2]|0?[1-9]/;
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* const h24 = /2[0-3]|[01][0-9]/;
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* const hours = XRegExp.tag('x')`${h12} : | ${h24}`;
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* const minutes = /^[0-5][0-9]$/;
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* // Note that explicitly naming the 'minutes' group is required for named backreferences
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* const time = XRegExp.tag('x')`^ ${hours} (?<minutes>${minutes}) $`;
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* time.test('10:59'); // -> true
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* XRegExp.exec('10:59', time).minutes; // -> '59'
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*/
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XRegExp.tag = (flags) => (literals, ...substitutions) => {
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const subpatterns = substitutions.map(interpolate).reduce(reduceToSubpatternsObject, {});
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const pattern = literals.raw.map(embedSubpatternAfter).join('');
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return XRegExp.build(pattern, subpatterns, flags);
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};
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/**
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* Builds regexes using named subpatterns, for readability and pattern reuse. Backreferences in
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* the outer pattern and provided subpatterns are automatically renumbered to work correctly.
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* Native flags used by provided subpatterns are ignored in favor of the `flags` argument.
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*
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* @memberOf XRegExp
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* @param {String} pattern XRegExp pattern using `{{name}}` for embedded subpatterns. Allows
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* `({{name}})` as shorthand for `(?<name>{{name}})`. Patterns cannot be embedded within
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* character classes.
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* @param {Object} subs Lookup object for named subpatterns. Values can be strings or regexes. A
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* leading `^` and trailing unescaped `$` are stripped from subpatterns, if both are present.
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* @param {String} [flags] Any combination of XRegExp flags.
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* @returns {RegExp} Regex with interpolated subpatterns.
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* @example
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*
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* const time = XRegExp.build('(?x)^ {{hours}} ({{minutes}}) $', {
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* hours: XRegExp.build('{{h12}} : | {{h24}}', {
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* h12: /1[0-2]|0?[1-9]/,
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* h24: /2[0-3]|[01][0-9]/
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* }, 'x'),
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* minutes: /^[0-5][0-9]$/
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* });
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* time.test('10:59'); // -> true
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* XRegExp.exec('10:59', time).minutes; // -> '59'
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*/
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XRegExp.build = (pattern, subs, flags) => {
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flags = flags || '';
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// Used with `asXRegExp` calls for `pattern` and subpatterns in `subs`, to work around how
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// some browsers convert `RegExp('\n')` to a regex that contains the literal characters `\`
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// and `n`. See more details at <https://github.com/slevithan/xregexp/pull/163>.
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const addFlagX = flags.includes('x');
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const inlineFlags = /^\(\?([\w$]+)\)/.exec(pattern);
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// Add flags within a leading mode modifier to the overall pattern's flags
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if (inlineFlags) {
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flags = XRegExp._clipDuplicates(flags + inlineFlags[1]);
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}
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const data = {};
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for (const p in subs) {
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if (subs.hasOwnProperty(p)) {
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// Passing to XRegExp enables extended syntax and ensures independent validity,
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// lest an unescaped `(`, `)`, `[`, or trailing `\` breaks the `(?:)` wrapper. For
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// subpatterns provided as native regexes, it dies on octals and adds the property
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// used to hold extended regex instance data, for simplicity.
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const sub = asXRegExp(subs[p], addFlagX);
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data[p] = {
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// Deanchoring allows embedding independently useful anchored regexes. If you
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// really need to keep your anchors, double them (i.e., `^^...$$`).
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pattern: deanchor(sub.source),
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names: sub[REGEX_DATA].captureNames || []
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};
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}
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}
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// Passing to XRegExp dies on octals and ensures the outer pattern is independently valid;
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// helps keep this simple. Named captures will be put back.
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const patternAsRegex = asXRegExp(pattern, addFlagX);
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// 'Caps' is short for 'captures'
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let numCaps = 0;
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let numPriorCaps;
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let numOuterCaps = 0;
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const outerCapsMap = [0];
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const outerCapNames = patternAsRegex[REGEX_DATA].captureNames || [];
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const output = patternAsRegex.source.replace(parts, ($0, $1, $2, $3, $4) => {
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const subName = $1 || $2;
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let capName;
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let intro;
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let localCapIndex;
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// Named subpattern
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if (subName) {
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if (!data.hasOwnProperty(subName)) {
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throw new ReferenceError(`Undefined property ${$0}`);
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}
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// Named subpattern was wrapped in a capturing group
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if ($1) {
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capName = outerCapNames[numOuterCaps];
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outerCapsMap[++numOuterCaps] = ++numCaps;
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// If it's a named group, preserve the name. Otherwise, use the subpattern name
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// as the capture name
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intro = `(?<${capName || subName}>`;
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} else {
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intro = '(?:';
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}
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numPriorCaps = numCaps;
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const rewrittenSubpattern = data[subName].pattern.replace(subParts, (match, paren, backref) => {
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// Capturing group
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if (paren) {
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capName = data[subName].names[numCaps - numPriorCaps];
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++numCaps;
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// If the current capture has a name, preserve the name
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if (capName) {
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return `(?<${capName}>`;
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}
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// Backreference
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} else if (backref) {
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localCapIndex = +backref - 1;
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// Rewrite the backreference
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return data[subName].names[localCapIndex] ?
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// Need to preserve the backreference name in case using flag `n`
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`\\k<${data[subName].names[localCapIndex]}>` :
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`\\${+backref + numPriorCaps}`;
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}
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return match;
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});
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return `${intro}${rewrittenSubpattern})`;
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}
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// Capturing group
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if ($3) {
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capName = outerCapNames[numOuterCaps];
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outerCapsMap[++numOuterCaps] = ++numCaps;
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// If the current capture has a name, preserve the name
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if (capName) {
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return `(?<${capName}>`;
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}
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// Backreference
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} else if ($4) {
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localCapIndex = +$4 - 1;
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// Rewrite the backreference
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return outerCapNames[localCapIndex] ?
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// Need to preserve the backreference name in case using flag `n`
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`\\k<${outerCapNames[localCapIndex]}>` :
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`\\${outerCapsMap[+$4]}`;
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}
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return $0;
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});
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return XRegExp(output, flags);
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};
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};
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